<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		<script type="text/javascript">
			var a = 1;
			function fun1(a){
				console.log(a);  // 1
				a+=1;
				return a; //函数的返回值
			}
			console.log(a);  //1
			a = fun1(a); 
			console.log(a); //2?
			
			/*************************/
			var a = 1;
			function fun2(b){
				console.log(b);  //1
				var b = 2;
				return b; //函数的返回值
			}
			console.log(a);  //1
			a = fun2(a); 
			console.log(a); //2
		</script>
	</body>
</html>
